Shoulder and Arm Flashcards
sternoclavicular joint? ligaments involved?
- connects manubrium of sternum and medial clavicle
- strengthened by joint capsule and anterior and posterior sternoclavicular ligaments
- also strengthened by costoclavicular ligaments
- only bone to bone joint that attaches upper limb to trunk of body
acromioclavicular joint? ligaments involved?
- connects acromion of scapula with the lateral clavicle
- strengthened by acromioclavicular ligament and coracoclavicular ligament (coracoid and clavicle)
- coracoclavicular ligament has two parts:
1. conoid ligament (medial)
2. trapezoid ligament (lateral)
Shoulder separation? 3 types?
- acromioclavicular joint separation
1. type 1- no fracture or tear (sprain)
2. type 2- complete tear of AC ligament
3. type 3- complete tear of AC and CC ligaments
Glenohumeral joint? capsule?
- glenoid labrum increases depth of cavity
- head of humerus held in place by rotator cuff muscles
- capsule:
- glenoid cavity to anatomical neck of humerus
- weakest inferiorly
Function of glenoid labrum? common tears?
- fibrocartilage ring
- deepens glenoid cavity
- tears common from throwing motion
- tears most often anterior superior
Ligaments of the glenohumeral joint?
- coracohumeral ligament
- coracoid process to greater tubercle
- strengthens superiorly - transverse humeral ligament
- greater to lesser tubercle of humerus (bicipital groove)
- holds long tendon of biceps brachii in place - coracoacromial ligament
- coracoid process and acromion
- strengthens joint superiorly
coracoacromial arch?
- coracoacromial ligament
- abduction:
- causes impingement of greater tubercle on acromion
- without rotation the greater tubercle contacts the arch preventing further movement
- with 180 degrees of lateral rotation complete abduction can occur
shoulder dislocation?
- dislocation of glenohumeral joint
- head of humerus driven inferior and anterior (95%)
- treatment:
- closed or open reduction
- pull inferiorly and laterally for closed reduction
scapulothoracic joint?
- scapula sits on top of ribs
- scapula moves:
- elevation
- depression
- protraction
- retraction
- rotation (up or down)
- rotation is important to allow more movement of humerus and to avoid soft tissue damage
Posterior thoracoappendicular muscles?
- trapezius
- lat dorsi
- rhomboids
- levator scapulae
Anterior thoracoappendicular muscles?
- pec major
- pec minor
- serratus anterior
- subclavius
Deltoid attachments?
- proximal:
- lateral third of clavicle
- acromion
- spine of scapula - distal:
- deltoid tuberosity
Deltoid innervation?
axillary nerve
Deltoid function?
- clavicular head: flexes and medially rotates arm
- acromial head: abducts arm after first 15 degrees to about 90 degrees
- spinal head: extends and laterally rotates arm
What are the rotator cuff muscles? functions?
- muscles (SITS)
- supraspinatus
- infraspinatus
- teres minor
- subscapularis - functions:
- form musculotendinous cuff around head of humerus
- reinforce capsule
- hold humeral head in glenoid fossa
- all rotate except supraspinatus (abducts)
Supraspinatus attachments?
- proximal:
- supraspinous fossa - distal:
- greater tubercle of humerus
Supraspinatus innervation?
suprascapular nerve
supraspinatus function?
- initiates abduction of arm, first 15 degrees
- person with damage to this muscle leans to one side in order to abduct by gravity and then deltoid kicks in
Infraspinatus attachments?
- proximal:
- infrapsinous fossa - distal:
- greater tubercle of humerus
Infraspinatus nerve?
suprascapular nerve
Infraspinatus function?
- laterally rotates arm
- holds head of humerus in glenoid fossa
Teres minor attachments?
- proximal:
- lateral border of scapula - distal:
- greater tubercle of humerus
Teres minor innervation?
axillary nerve